How to prepare Sentinel-1 images stack for PSI/SBAS in SNAP

Microwave Toolbox StaMPS
#375

Dear all,

As you can see in my previous post I had the problem regarding the proper position of my PS pixels. I found the new version of SNAP by chance and in its Remove Topo tool has been added an ''oethorectified lat/long option (i.e. in the parameter section) as @mfitrzyk already mentioned. So, we do not need to geocode the needed files for STAMPS exporting anymore. My problem was solved by using the new version of SNAP (see below photo). I thought it worth sharing to save the time. Merry Christmas and happy New Year.

my final.png1490×625 1.96 MB

3 Likes
StaMPS - Detailed instructions
#376

Hi all,
I processed 32 SLCs finally and the values of my results change between +20 and -30 mm/year (LOS velocity). I processed VV components and the negative values means subsidience after earthquake and but what does the mean of positive values ? I checked all unwrapped phases and the changes only occurs after earthquakes that bigger than 6.5 Mw. I showed normal and shaded relief verison of mean los velocity map. Thanks.
Fikret

Resim1.jpg1813×1029 307 KB
Resim2.png1449×823 2.1 MB

6 Likes
#377

Dear @Mehdi Im glad you have managed to process the data correctly.
Keep in ind that this version of the software is not an official release - just release candidate
The official release should be in the next couple of days!

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#378

Hi All

I don’t have the INSAR_master_date folder’s in my data of StaMPS.v3, I redirected all (geo, dem, dff0, rslc) in other folder and other directory… but when I run the command (mt_prep_gamma 20160208 0.4 2 2 50 200) this give me a error…
below print screen StaMPS.v3

image.jpg1024×768 214 KB

my question is: Is necessary that all folder is in the same directory???

below print screen PSI_RESULTADOS

image.jpg1024×768 135 KB

#379

I don’t know if I understood correctly, but you should call mt_prep_gamma command from folder where your exported files are (from PSI_RESULTADOS). Before that you should add bin folder from StaMPS directory to path variables.

#380

Hi Fikretjfm,
The velocity map you get is only a relative value, the zero values on the map don’t mean they don’t subsidence in reality, they are just the reference points. For example, if the subsidence velocity of the zero value points on the map is 20mm/yr in reality, then the real subsidence velocity of the points which value are -5mm/yr on the map is 15mm/yr, and the positive values on the map are calculated the same way.
All the best,
Fei

3 Likes
#381

Thanks @jozep for your reply

Path variables??? Please, do you can explain me?

#382
#384

You are unable to run the command as the system doesn’t know where to look for the mt_prep_gamma script file.

Open a Terminal window.

To add the directory of the mt_prep_gamma script (in this case the StaMPS bin directory) to the path list type:

PATH=/yourStaMPSfolderdirectory/bin:$PATH.

You should now be able to execute the command.

To check the updated environment variable path list type:

echo $PATH

The newly added path should appear in the list.

To run the command and avoid any errors you can format it as follows:

mt_prep_gamma [yyyy/mm/dd - of master scene] [output_directory] 0.4 2 2 50 200

(given that you want to leave the default prep options)

Good luck

#385

Hi @kouhartsiouk

Thanks for your reply, before I make your suggested me, I have that to install the tcsh program!!! :disappointed_relieved:

#386

Hello everyone,

I followed the steps which Katherine provided and get weird wrapping result in StaMPS as below. Do you have any suggestion on this issue? Btw, unwrapping or plot any figure will have similar issue.
Many thanks.

#390

#######################################################

Warning

The workflow described in this post (and the ones referring to it later on) is outdated and no longer recommended, because new versions of SNAP and StaMPS have been released. Please have a look at this updated list of instructions: StaMPS - Detailled instructions
#######################################################

Hi all,
Recently SNAP6.0 has been released, and by chance @Mehdi use the “oethorectified lat/long” options to solve his problem. And now I test this method and find that this new option can solve the shift problem and can avoid Terrain Correction (TC) step in PSI. @katherine @annamaria @bayzidul @ABraun
Here is the new Interferogram Formation window in SNAP6.0:

After finish this step, elevation and lat/lon band will be generated in result product.

Start from Deburst step, we get Stack_deb, then create a subset, get Subset_Stack_deb, form interfeorgrams as the first picture showed and get Subset_Stack_deb_ifg. And then use Subset_Stack_deb and Subset_Stack_deb_ifg to export to StaMPS.
And that’s all, all the things have been done. Add Elevation band, geocoded and topo_removal are doing together in interferogram formation step, TC are avoided, lat/lon file can export correctly without saving to GAMMA format.

Here are some results:
1.use SNAP6.preview4 and without TC:

4.PNG880×431 748 KB

2.use SNAP6.preview4 and TC:
5.PNG848×379 628 KB

3.use SNAP6.0 oethorectified lat/lon and without TC:
6.PNG1029×444 865 KB

Note: I use different parameters when export to Google Earth, and only about 20% PSs are shown in the picture, so don’t be surprised that PSs location are not exactly the same.

In SNAP6.preview4 or preview5, without TC there are exist shift problem. And use SNAP6.0, shift problem has been solved and TC are no more needed.

Have Fun!
Fei

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Workflow between SNAP and StaMPS
StaMPS - Detailed instructions
#391

that’s just fantastic, thanks for testing!

One question about the stack: Did you create pairwise stacks of AB AC AD… and merge them with the back geocoding as originally suggested? Because this creates a quite redundant stack with A in it multiple times and I wondered if this is the best way to do it.

#392

Dear ABraun,
I follow the step as katherine suggested here:


And my post can be seen as a suggestion for the orignal way.

1 Like
#393

Dear Fei,
Thank you so much for sharing your wonderful experience! Due to our cooperation the workflow between SNAP and StaMPS becomes more and more friendly! The next problem seems to be the possibility to create a stack of pairs with different masters (being resampled to one “supermaster”) and export such a stack to StaMPS to execute the StaMPS SB (Small Baselines Processing). StaMPS SB will be very useful in rural areas where StaMPS PS permits us to identify only few PS (especially using S-1 images)…
All the best,
Katherine

1 Like
#394

Hi @kouhartsiouk @Fikretjfm

I have a problem during the processing final, the process stopped for 20170409, and when I check the folder .rslc I can see the archive 20170409 duplicate, someone had the same problem?

Thanks for advance

#396

Dear Katherine,
Thank you for your reply, I also notice that almost all the PSs points I get are located in urban area, and get only few PSs in rural area. It’s a shortage for StaMPS PS method, and can hope SB method to improve it.
But it seems that the implemention of SBAS export in SNAP have to wait a long time…:joy:
All the best,
Fei

#397

maybe the file was still in use by another program? Does it always happen with that date?

#398

hi ,
have you tried to delete one of them? I havent faced such a this error.
Fikret

#399

Thank you for the test-report Fei!